Quaternary ammonium anion exchange resins and method for preparing the same



United States Patent QUATERNARY AMMONIUM ANION EXCHANGE ISRXSINS ANDMETHOD FOR PREPARING THE- Albert H. Greer, Westmont, N. J., assignor toThe Permutit Company, New York, N. Y., a corporation of Delaware NoDrawing. Application March 30, 1953,

Serial No. 345,680

17 Claims. (Cl. 260-2.!)

The present application is a continuation-in-part of my copendingapplication, Serial Number 304,009, filed August 12, 1952.

The present invention relates to novel, synthetic polymeric compositionswhich are useful in the removal of anions from aqueous solutions and toa novel method for preparing said compositions. The invention alsorelates to a method of removing anions from an aqueous solution.

Anion exchange resins, in order to be satisfactory for use, must besubstantially insoluble in water, dilute acids and alkalies. They mustbe capable of resisting physical transformation, such as undue swelling,or mechanical disintegration, such as spalling or shattering of theresin beads and granules, when in contact with the solution they areused to deionize. They must also have a high useful or operatingcapacity for removing anions from aqueous solutions, and be capable ofbeing repeatedly regenerated for reuse when they become exhausted. It isalso desirable that in addition to a high operating ca pacity, the resinhave a high capacity for removing the weaker anions from solution, suchas silica and carbon dioxide.

It is an object of the present invention to provide a novel anionexchange resin which, while possessing all of the essential propertiesof a successful anion exchange resin, possesses an unusually highoperating capacity and particularly a high capacity for the removal ofweaker anions from aqueous solutions.

It is a further object to provide a novel process for the removal ofanions, and especially weaker anions, from aqueous solutions.

It is an additional object to provide a novel process for producing thenovel anion exchange resins of the present invention.

Other objects will be apparent to those skilled in the art from areading of the descriptions which follows.

My invention comprises, in part, novel, synthetic polymeric anionexchange resins containing one and preferably two or more (di and poly)quaternary ammonium substituents per molecular unit of polymeric resin.The polymeric resin moiety of the anion exchanger shall be a copolymerof a vinyl substituted, cyclic compound having an active hydrogensubstituent and having a ring activating substituent and an unsaturatedcrosslinking compound. The activated nucleus shall be suitablysubstituted with at least one quaternary ammonium group and shalldesirably contain two or more quaternary ammonium groups. Preferably,the quaternary ammonium groups shall be alkyl or alkyl-alkanolsubstituted quaternary ammonium groups.

The vinyl substituted, cyclic compound, which forms part of the anionexchange resin, and which contains an active hydrogen substituent, shallbe one containing one or more hydrogen atoms which are made reactive bythe effect of another substituent of the cyclic nucleus which activatesthe ring, such as a hydroxyl group; to produce a vinyl substitutedphenol, a hydroquinone group; to pro- Patented July 30, 1957 duce vinylsubstituted benzohydroquinones or napbthohydroquinones; such compoundsas vinyl cyclohexanone, vinyl cyclopentanone, vinyl antipyrine, vinylmethyl thiophene and vinyl methyl furan; or preferably a vinylsubstituted, alkyl substituted, heterocyclic compound which is activatedby the presence of a nitrogen atom in the aromatic ring. In each ofthese compounds there is a group substituted upon or an atom which ispart of the cyclic nucleus which activates the ring and consequentlyactivates one or more hydrogen containing substituents of the same ring.Thus the hydroxyl group activates the ring of the phenol group, thehydroquinone group activates a ring of benzohydroquinone andnaphthohydroquinone compounds, the ketone group activates thecyclohexane and cyclopentane rings and the sulfur, oxygen and nitrogenatoms in the heterocyclic nuclei activate the heterocyclic nuclei ofthiophene, furan and pyridine containing compounds.

The preferred vinyl substituted, nitrogen-containing heterocycliccompounds are those of the alkyl pyridines, preferably methyl pyridine.However, other vinyl substituted, nitrogen containing heterocycliccompounds may be used, such as the alkyl substituted, and preferably themethyl substituted, vinyl pyrroles, pyrimidines, pyridazines, pyrazines,quinolines and isoquinolines.

Among the specific vinyl derivatives of alkyl substituted, nitrogencontaining heterocyclic compounds contemplated, are the vinyl methylpyridines in which the methyl group is substituted in the 2, 4 or 6positions. These include Z-methyl-S-vinyl pyridine, 4-methyl-5-vinylpyridine and 2,4-dimethyl-5-vinyl pyridine. Other compounds are: thevinyl methyl quinolines such as Z-methyl- 5-vinyl quinoline,4-methyl-5-vinyl quinoline, the isoquinolines, such as l-methylorS-methyl-S-vinyl isoquinoline. Based upon experience to date,Z-methyl-S-vinyl pyridine is preferred.

The other component of the coplymer is an unsaturated crosslinkingcompound. This is a well defined type of compound having the faculty ofpolymerizing with vinyl substituted compounds to form an insolubleresin. They may be polyvinyl aromatic or aliphatic unsaturatedcompounds. The most important type of crosslinkers are the polyvinylarylcompounds, such as the divinyl and other polyvinyl benzenes, includingtrivinyl and tetravinyl benzenes, divinyl toluenes and alkylbenzenes,xylenes, naphthylenes and diphenyls. Other crosslinking compounds whichmay be used advantageously are unsaturated aliphatic compoundscontaining two unsaturated groups, desirably two double bonds. Examplesof these are: divinyl sulfone; divinyl ketone; vinyl ethinylhydrocarbons such as vinyl acetylene and divinyl acetylene; vinylmaleate; vinyl esters of acrylic, methacrylic and ethacrylic acids, suchas vinyl acrylate, vinyl methacrylate and vinyl ethacrylate; divinylesters of dibasic acids, such as divinyl oxylate, divinyl maleate,divinyl malonate and divinyl succinate; and acrylic diesters of analiphatic polyhydric alcohol, such as diethylene glycol dimethacrylate,ethylene glycol dimethacrylate, diethylene glycol diacrylate, glycerinedimethacrylate and ethylene glycol diacrylate. Other unsaturatedaliphatic groups than the vinyl group may be used, although the groupshould preferably have a terminal double bond. Among such groups whichmay be used to replace the vinyl group are the allyl group, the3-n-butenyl group, etc. To date, divinylbenzene has proven the mostsuitable for use in the copolymer of the invention.

While, as explained above, the copolymer may be based upon any vinylsubstituted, cyclic compound, having an active hydrogen substituent, forpurposes of illustration one of the more specific phases of the basicanion exchange resins will be described in relation to the use of 32-methyl-5-vinyl pyridine as the basic component of the copolymer. Thestructure described is based on a molecular unit of 2-methyl-5-vinylpyridine.

In the above formula R, R1, R and R3 are members selected from the classconsisting of alkyl, alkanol and aralkyl groups. R4 is a lower alkylenegroup and preferably an ethylene group. R, R1, R2, and R are preferablylower in size containing not more than 8 carbon atoms and preferably notmore than 4 carbon atoms. When these groups are alkyl groups, bestresults are obtained when they are methyl or ethyl groups. The mostsuitable alkanol group is the ethanol group. X1 and X2 are anions andneed not be identical. It is desirable that X1 and X2 be anions of astrong acid, such as a mineral acid. For anion exchange purposes, it isrecommended that both Xs be hydroxyl groups.

If the pyridine ring in the above formula contains ad ditional alkylsubstituents, these may become substituted with additional quaternaryammonium groups when the copolymer resin is subjected to the process ofthe invention. It is to be understood that the alkyl group initiallysubstituted on the pyridine ring should be in the 2, 4 or 6 positionswith respect to the ring nitrogen atom, and that the alkyl grouppreferably is a methyl group containing an active hydrogen atom, if thealkyl group is to be substituted with a quaternary ammonium group whensub jected to the process to be described. If the heterocyclic ringcontains a second nitrogen atom, this may additionally form anotherquaternary ammonium group when treated with a quaternizing agent.

It will be evident from the structure of the pyridine moiety of thecopolymer that there are at least two quaternary ammonium groups perheterocyclic unit; one of which is formed in part by the nitrogencontained in the ring and another is attached to the ring through alower alkylene group. tuted-vinyl substituted-nitrogen containingheterocyclic compounds are preferred, as the capacities of the anionexchange resin will be a function of the number of quaternary ammoniumgroups.

While a definite structure has been assigned to the anion exchange resinillustrated by the above structural formula, this is done for purposesof illustration only. The struc ture of the anion exchange resin is notto be restricted by any theory of reaction mechanism for the novelprocess which comprises part of the invention. While the structureassigned for the product is based upon the most recently availablescientific information, it is possible that a different structuralrelationship may exist, but should this be true, the composition willstill be composed of the same essential chemical constituents described.In a manner of speaking, the highly basic anion exchange resins of theinvention may be said to comprise those products produced by the novelprocess of the invention. Thus a copolymer obtained from a vinylsubstituted cyclic compound having at least one substitutent hydrogenatom of pronounced reactivity which is capable of condensation withammonia, or a primary or secondary amine or the hydrohalide salts ofthese amines and a lower aldehyde is satisfactory for use in the processof the invention, and it is the resulting anion exchange resins whichare the sub ject of the present invention.

The preferred polymerizate is that prepared by copolymerizing avinyl-alkyl-pyridine, and suitably Z-methyl- S-vinyl-pyridine, anddivinyl benzene; the latter serving as the crosslinker. It is preferredthat the vinyl-alkyl-pyri- It is for this reason that the alkylsubstidine constitute from 60.0 to 99.9%, on a molar basis, of thepolymerizate and that the crosslinker constitute 0.1 to 40.0% of thepolymerized mixture, on a molar basis. Best results are obtained whenthe alkyl-vinyl-pyridine constitutes 85.0 to 99.5% of the polymerizateand the crosslinker from 0.5 to 15.0% (both on a weight basis). Theoptimum composition of the polymerizate is one prepared from 10% byweight of crosslinker and by Weight of the alkyl-vinyl-pyridine. Apolymerizate having a particle size range of between 16 to 50 mesh ismost desired.

The present invention also comprises the novel process for preparing thenovel anion exchange resins of the invention. In preparing my anionexchange resins, I first prepare the copolymer resin. The copolymerresin is then subjected to the process of the invention which comprisescondensing the copolymer resin with a lower aldehyde containing not morethan three carbon atoms and a member selected from the class consistingof ammonia and primary and secondary amines. The essential feature ofthis process is the replacement of an active hydrogen atom contained inthe copolymer resin by an amino-alkyl or substituted amino-alkyl group.If the condensation is effected with a primary amine, or its salt, theproduct is a secondary amine and similarly if a secondary amine is usedin the condensation, a tertiary amine is produced. The use of ammoniaresults in a primary amine. Since the final product is desirably aquaternary ammonium salt, it is preferable to use a secondary amine inthe condensation because of the smaller amount of the comparativelyexpensive quaternizing agent required to convert the amine to thequarternary form. After the condensation has been completed, theresultant amine is converted to the corresponding quaternary ammoniumsalt by treatment with a quaternizing agent.

Optionally, one may quaternize the nitrogen atom of a heterocyclic ringprior to the condensation step as Well as subsequent to condensation. Inparticular, if the copolymer of 2-methyl-5-vinyl pyridine and divinylbenzene is treated with a quaternizing agent, the resulting quaternaryammonium polymer is then treated with a secondary amine and formaldehydeand the resulting quaternary, tertiary amine is treated with aquaternizing agent, there is produced the di-quaternary ammoniumderivative.

The copolymer resin is prepared by reacting the vinyl substituted,cyclic compound, which contains an active hydrogen substitutent andhaving a ring activating substituent, with the crosslinking compound inthe presence of an oxidizing catalyst such as oxygen, azobisisobutyro:nitrile, organic peroxides, such as benzoyl peroxide, lauroyl peroxide,tertiary alkyl peroxides, di (tertiary alkyl) peroxides, and persalts,such as potassium persulfate, etc. The catalyst may be used in varyingamounts and desirably from 0.01 to about 5 parts per parts of totalmonomer. The polymerization may be conducted in an aqueous emulsion orin an inert organic solvent.

The condensation step is conducted upon the copolymer resin by reactingit with a lower aldehyde containing not more than 3 carbon atoms inconjunction with ammonia or a primary or secondary amine. The preferredaldehyde is formaldehyde and its commercially available forms, such asformalin and para-formaldehyde. Other aldehydes which may be used areacetaldehyde and propylaldehyde.

Among the amine which may be used in the condensalion step are thesecondary amines, including the lower dialkyl amines, such asdimethylamine, diethylamine, dipropylamine and di-n-butylamine; thelower alkanol amines such as methyl ethanol amine, ethyl ethanol amine,and diethanolamine; the aralkylamines such as dibenzylamine,methylaniline; and the cyclic amines such as piperazine, piperidine andmorpholine. Additionally, the corresponding primary amines of thosementioned may be used in effecting the condensation. If so, additionalamounts of quaternizing agent will be required to convert the resultingsecondary amine into a quaternary ammonia salt. The acid addition saltsof the above amines may also be used, and among these are thehydrochlorides, hydrosulfates, etc. Also, ammonia may be used; however,this is not preferred.

The amine derivative resulting from the condensation process, as well asany nitrogen contained in a heterocyclic ring, may be converted to thecorresponding quaternary ammonia groups by treatment with a quaternizingagent. Among this well known group of chemical reagents are the alkylhalides, such as methyl chloride, bromide and iodide, ethyl chloride,bromide and iodide, etc.; dialkyl sulfates, such as dimethyl, diethyl,dipropyl, dibutyl sulfates; epihalohydrins, such as epichlorohydrin; andalkyl esters of aryl sulfonates, such as methyl toluene sulfonate andmethyl benzene sulfonate.

The invention also comprises the novel process for re moving anions froman aqueous solution, comprising contacting the solution with thequaternary ammonium derivative of the copolyrnerizates of the invention.The quaternary ammonium derivates of the copolymerizates are present insufiicient quantity to remove substantially all the anions from aqueoussolution. This may be done by passing the solution through a columnpacked with the anion exchange resin. The anion may be removedsatisfactorily from the resin and the resin thus regenerated by washingit with a dilute alkali, preferably sodium hydroxide, which alkali willform a soluble salt with the adsorbed anions.

In order to disclose more clearly the nature of the present invention,specific examples illustrating the preparation of typical compounds willhereinafter be described. This is done solely by way of example and isintended neither to delineate the scope of the invention nor limit theambit of the appended claims.

EXAMPLE 1 A. Preparation of copolymer resin A copolymer resin wasprepared which consisted of a 7% crosslinker in the following manner: Toabout 900 ml. of water heated to 5080 C. was added a mixture of 261.3 g.of Z-methyl-S-vinyl pyridine, 38.7 g. of divinylbenzene solutioncontaining 54.8% strength divinyl benzene and 45.2% strength ethylstyrene with 2.2 g. of benzoyl peroxide dissolved therein. After heatingfor three to six hours at 50-80 C., with stirring, the polymerizationwas complete. The resulting product which was in the shape of solidspheroids was washed with water and dried at 220-300 F. for three to sixhours. The yield was nearly quantitative.

B. Preparation of tertiary amino-methyl derivative of resin About 119 g.of the beads of copolymer resin prepared in Part A was suspended in 276g. of a 32.6% solution of dimethylamine in water. The mixture was cooledto 15 C. and 162 g. of a 37 solution of formaldehyde in water was addedwith stirring at such a rate as to keep the temperature below 30 C.After addition of reagents had taken place, the suspension was heated to50 C. and stirring continued for 6 to 8 hours. The beads were filteredfrom solution and washed with water and airdried.

C. Qunterniznzion of tertiary amino-methyl derivative The entire productobtained from Part B was slurried in methanol and 300 g. of methyliodide added at one time. The mixture was stirred and heated underreflux for 6 hours. The product was filtered, washed with methanol andthen with water. The resulting resin when regenerated with 5% sodiumhydroxide solution to place it in the hydroxide exchanging condition wasfound to have a basicity value of 17.4 kgn/cu. ft., an ultimate capacityof 27.8 kgn/cu. ft. and a density of 346 g./'liter.

EXAMPLE 2 A. Preparation of tertiary alkanolamino-methyl derivative ofresin About 119 g. of cross-linked polymer resin prepared in Part A,Example 1, was suspended in 150 g. of methyl ethanolamine dissolved in150 g. of water. The mix ture was cooled to 15 C. and 162 g. of a 37%solution of formaldehyde in Water was added with stirring at such a rateto keep the temperature below 30 C. After this addition, the mixture washeated to 50 C. and stirring continued for an additional six hours atthis temperature. The product was filtered and washed with water.

B. Quaternization of tertiary alkmzoI-amino-methyl derivative '1 heaminated product from Part A was suspended in enough methanol to form aslurry and then 300 g. of methyl iodide was added with stirring. Themixture was heated under reflux for six hours. The product was filtered,washed with methanol and then with water. The material was regeneratedwith a 5% sodium hydroxide solution to convert it to the hydroxideexchanging condi tion and found to have a basicity value of 15.5kgr./cu. it, an ultimate capacity of 22.3 lcgnfcu. ft.. and a density of299 g./liter.

EXAMPLE 3 A. Preparation of tertiary amino-methyl derivative of resinAbout sixty-one grams of a 7.5% cross-linked polymer resin, prepared inthe same manner as described in Part A of Example 1, was swollen inmethanol for thirty minutes, filtered and placed wet in 180 g. of a 25%solution of dimethylamine in water. The mixture was cooled to 15 C. and81 g. of a 37% solution of formaldehyde in water was added with stirringat a temperature below 30 C. After addition, the stirring was continuedand the material was heated to 50 C. for 5 hours. The material wasfiltered, washed with water and air-dried.

B. Quaterm'zation of tertiary amino-methyl derivative The materialobtained in Part A above was suspended in 100 ml. of water, 2 g. ofsodium hydroxide was added and then 135 ml. of dimethylsulfate was addedwith stirring. An exothermic reaction occurred. After the reactionsubsided, stirring was continued for six hours at C. The mixture wascooled, neutralized with ammonia and filtered. The beads were washedwith water, and regenerated with 5% sodium hydroxide to convert theproduct to the hydroxide exchanging condition. The resin had a basicityvalue of 16.3 kgr./cu. ft., an operating capacity of 14.2 kgr./cu. ft.[with water containing 50 p. p. m. of free mineral acids and 16 p. p. m.silica (both reported as parts of calcium carbonate)], an ultimatecapacity of 24.1 kgr./cu. ft. and a density of 268 g./liter.

EXAMPLE 4 A. Preparation of tertiary amino-methyl derivative of resinAbout sixty-one grams of a copolymer resin containing 7.5%cross-linking, prepared as described in Part A, Example 1, was suspendedin 150 ml. of methanol for thirty minutes and then filtered. The wetbeads were suspended in 73 g. of diethylamine and then 81 g. of a 40%solution of formaldehyde in methanol was added with stirring at atemperature below 30 C. After this addition, the mixture was heated to60 C. for 6 hours. The beads were filtered, washed with water andair-dried.

B. Quaternization of tertiary amino-methyl derivative The aminatedproduct from the above reaction (Part A) was suspended in ml. of watercontaining 2 g. of sodium hydroxide. Stirring was begun and ml. ofdimethyl sulfate was added. The temperature was slowly raised to 70 C.and held at this temperature for 6 hours.

The mixture was neutralized with ammonia and filtered. The water washedbeads were regenerated with sodium hydroxide to convert them to thehydroxide exchanging condition and the resin was found to have abasicity value of 18.1 kgr./cu. it, an operating capacity of 14.5kgr./cu. ft. [with water containing 50 p. p. m. of free mineral acidsand 16 p. p. m. of silica (both reported as parts of calciumcarbonute)], an ultimate capacity of 27.1 kgr./cu. ft., and a density of280 g./liter.

EXAMPLE 5 A. Preparation of tertiary amino-methyl derivative of resinAbout sixty-one grams of a copolymer containing 9% cross-linker preparedby the method described in Example I, Part A, was swollen in propylenedichloride for minutes, filtered and suspended in 87 g. of morpholine.Eighty-one grams of a 40% solution of formaldehyde in methanol was addedduring 0.5 hour at 30-40 stirring. The reaction was continued at 60 for6 hours. The material was filtered and washed with water.

H. Quaternization of tertiary amino-methyl derivative of resin Theaminated product of Part A was suspended in 100 ml. water containing 2g. of NaOH and then 100 g. of dimethyl sulfate was added with stirring.The temperature was kept at 70 C. for seven hours. The product wasremoved, washed with water and regenerated with 5% caustic to convert tothe hydroxide exchanging condition and found to have a basicity value of16.7 kgr./cu. ft., an operating capacity of 15.2 kgr./cu. ft. [usingwater containing 50 p. p. m. of free mineral acids and 16 p. p. m. ofsilica (both reported as parts of calcium carbonate)], an ultimatecapacity of 29.4 kgr./cu. ft., and a density of 333 g./liter.

EXAMPLE 6 A. Initial quaternization of resin p. s. i. at 50 C. Themixture was acidified with hydrochloric acid, filtered, washed andair-dried.

B. Tertiary amino-methylization of resin followed by finalquaternization About 86 g. of the material from Part A, which had abasicity value of 9.4 kgr./cu. ft., was suspended in propylenedichloride for thirty minutes and then filtered. The material was thensuspended in 180 ml. of a solution of dimethylamine in water and 81 g.of 37% solution of formaldehyde in water was added with stirring during0.5 hour at C. The mixture was then heated to 50 C. for 6 hours withstirring. The material was then filtered, washed with water andsuspended in 100 ml. of water containing 2 g. of dissolved sodiumhydroxide and 50 g. of dimethylsulfate was added with stirring. Themixture was heated to 70 C. for six hours. The resin was filtered fromsolution, washed with water and regenerated with 5% sodium hydroxidesolution to convert to the hydroxide exchanging condition, and was foundto have a basicity value of 16.9 kgr./cu. ft., an operating capacity of12.2 kgr./cu. ft. [using water containing 50 p. p. m. of free mineralacids and 16 p. p. m. of silica (both reported as parts of calciumcarbonate)], an ultimate capacity of 25.1 kgr./cu. ft.. and a density of304 g./liter.

EVALUATION TESTS Certain data are given for the products prepared in theabove examples which are of value in assessing the usefulness of highlybasic anion exchange resins. The

method used for determining those values which are not the subject ofstandardized tests is described below.

As used in the examples and elsewhere in this specification, the termbasicity value (sometimes referred to as salt-splitting capacity) is ameasure of the capacity of the anion exchange resin to remove the anionsof weak acids. Since the value of a highly basic anion exchange resinmay often reside in its ability to remove the anions of weak acids, aswell as those of strong acids, this is a critical value of theperformance of any basic anion exchange resin. As expressed here, thisvalue is obtained by passing 270 ml. of a 075 normal sodium hydroxidesolution through a 16 mm. column contain ing 40 ml. of the anionexchange resin at a flow rate of approximately 5 ml. per minute. Thisplaces the anion exchange resin or polymerizate in the hydroxideexchanging condition. The resin bed is rinsed as free as possible ofphenolphthalein alkalinity with distilled Water. 750 ml. of 0.5 normalsodium chloride solution is next passed through the resin bed at a flowrate of 7.5 ml. per minute. The column is washed with distilled water.The effluent and washings from the sodium chloride treatment arecollected, mixed and titrated with 0.02 normal sulfuric acid solution toa methyl orange endpoint. Since the strongly basic anion exchange resinwill remove chloride ion from the sodium chloride solution and convertsodium chloride to sodium hydroxide, this determination permits thecalculation of the sodium chloride converted to sodium hydroxide givingthe basicity value" capacity of the anion exchange resin. This sodiumchloride splitting value is expressed in kilograins of calcium carbonateper cubic foot of anion exchange resin. Resins having a high basicityvalue will have a high capacity for the removal of weak acids, such assilicic acid and carbonic acid from solutions.

The term ultimate capacity used in the examples and elsewhere in thespecification is determined by placing 40 ml. of resin, which has firstbeen placed in the chloride form by passing an excess solution of dilutehydrochloric acid over the resin followed by washing with water, in acolumn of 16 mm. size and through this column is passed 1000 ml. of 0.75normal sodium hydroxide at the rate of 5 m1./min. The resin bed is thenwashed free of phenolphthalein alkalinity with distilled water. Next 800ml. of 0.25 normal hydrochloric sulfuric acid solution (a ratio of 1.5parts of hydrochloric to 2.5 parts of sulfuric) is passed through theresin bed at a flow rate of 10 ml./min. Next 700 m]. of distilled wateris passed through the tube. The efiluent is collected and mixed and analiquot is titrated to determine the residual acid. From this, the totalamount of acid absorbed may be computed in terms of kgr./cu. ft. ofcalcium carbonate which gives the total or ultimate capacity of theresin.

As has been stated earlier in this specification, reactants other thanthose utilized in the specific examples above may be used and in whichcase, other quaternary ammonium derivatives of the copolymers may beprepared in accordance with the scope of the invention. Thus, othercrosslinkers, vinyl substituted cyclic compounds having an activehydrogen substituent, lower aldehydes, primary and secondary amines aswell as ammonia, and quaternizing agents may be used.

It is desirable that for use as anion exchange resins, the quaternaryammonium derivatives of the copolymers of the invention be converted tothe corresponding quaternary ammouium hydroxide derivatives. This resultis accomplished by passing a dilute aqueous solution of an alkali, suchas sodium hydroxide, over the quaternary ammonium derivative of thecopolymer.

The terms and expressions which I have employed are used as terms ofdescription and not of limitation, and I have no intention, in the useof such terms and expressions, of excluding any equivalents of thefeatures shown and described or portions thereof, but recognize thatvarious modifications are possible within the scope of the inventionclaimed.

What is claimed is:

1. A highly basic anion exchange resin comprising a copolymer of about60% to 99.9% on a molar basis of a vinyl methyl pyridine and about 40%to 0.1% on a molar basis of a crosslinker compound selected from theclass consisting of polymerizable polyvinyl aromatic and polyvinylaliphatic compounds; said vinyl methyl pyridine moiety having the methylgroup in a position selected from the group consisting of the 2, 4 and 6positions with respect to the nitrogen of the pyridine ring; saidcopolymer having quaternary ammonium methyl groups attached to themethyl groups on the pyridine nuclei to constitute quaternary ammoniumethyl groups attached to the pyridine nuclei; the ring nitrogen atoms ofthe pyridine being quaternized; the quaternizing substituent groups ofeach of the quaternary ammonium groups being a member selected from theclass consisting of alkyl, aralkyl and alkanol groups; said quaternaryammonium groups being neutralized by anions.

2. A highly basic anion exchange resin comprising a copolymer of about60% to 99.9% on a molar basis of a vinyl methyl pyridine and about 40%to 0.1% on a molar basis of a crosslinker compound selected from theclass consisting of polymerizable polyvinyl aromatic and polyvinylaliphatic compounds; said vinyl methyl pyridine moiety having the methylgroup in a position alpha to the nitrogen of the pyridine ring; saidcopolymer having quaternary ammonium methyl groups attached to themethyl groups on the pyridine nuclei to constitute quaternary ammoniumethyl groups attached to the pyridine nuclei in a position alpha to thenitrogen of the pyridine ring; the ring nitrogen atoms of the pyridinebeing quaternized; the quaterizing substituent groups of each of thequaternary ammonium groups being a member selected from the classconsisting of alkyl, aralkyl and alkanol groups; said quaternaryammonium groups being neutralized by anions.

3. A highly basic anion exchange resin as defined by claim 2, whereinthe vinyl methyl pyridine moiety is vinyl-Z-methyl pyridine.

4. A highly basic anion exchange resin as defined by claim 2, whereinthe crosslinking compound is divinyl benzene.

5. A highly basic anion exchange resin as defined by claim 2, whereinthe crosslinking compound is divinyl ketone.

6. A highly basic anion exchange resin as defined by claim 2, whereinthe crosslinking compound is a vinyl ester of a dibasic acid.

7. A highly basic anion exchange resin as defined by claim 2, whereinthe crosslinking compound is an acrylic diester of an aliphaticpolyhydric alcohol.

8. A highly basic anion exchange resin as defined by claim 2, whereinthe crosslinking compound is the vinyl ester of methacrylic acid.

9. A highly basic anion exchange resin comprising a copolymer of about85% to 95% by weight of 5-vinyl-2- methyl pyridine and about to 5% byweight of divinyl benzene; said copolymer having quaternary ammoniummethyl groups attached to the methyl groups on the pyridine nuclei toconstitute quaternary ammonium ethyl groups attached to the pyridinenuclei in a position alpha to the nitrogen of the pyridine ring; thering nitrogen atoms of the pyridine being quaternized; the quaternizingsubstituent groups of each of the quaternary ammonium groups being amember selected from the class consisting of alkyl, aralkyl and alkanolgroups; said quarternary ammonuim groups being neutralized by anions.

10. A highly basic anion exchange resin comprising a copolymer of about85% to 95% by weight of 5-vinyl-2- methyl pyridine and about 15% to 5%by Weight of 10 divinyl benzene; said copolymer having dimethylethanolammonium methyl halide groups attached to the methyl groups on thepyridine nuclei to constitute dimethylethanolammonuim ethyl halidegroups attached to the pyridine ring in a position alpha to the nitrogenof the pyridine ring; said copolymer having the ring nitrogen atoms ofthe pyridine rings quaternized with an alkyl halide; said quaternaryammonium groups being neutralized by anions.

11. A highly basic anion exchange resin comprising a copeiymer of aboutto by weight of 5-vinyl-2- methyl pyridine and about 15% to 5% by Weightof divinyl benzene; said copolymer having trimethylammonium methylhalide groups attached to the methyl groups on the pyridine nuclei toconstitute trimethylammonium ethyl halide groups attached to thepyridine ring in a position alpha to the nitrogen of the pyridine ring;said copolymer having the ring nitrogen atoms of the pyridine ringsquaternized with an alkyl halide; said quaternary ammonium groups beingneutralized by anions.

12. A process for preparing a highly basic anion exchange resincomprising a copolymer of about 60% to 99.9% on a molar basis of a vinylmethyl pyridine and about 40% to 0.1% on a molar basis of a crosslinkercompound selected from the class consisting of polymerizable polyvinylaromatic and aliphatic compounds; said vinyl methyl pyridine moietyhaving the methyl group in a position selected from the group consistingof the 2, 4 and 6 positions with respect to the nitrogen of the pyridinering; said copolymer having quaternary ammonium methyl groups attachedto the methyl groups on the pyridine nuclei to constitute quaternaryammonium ethyl groups attached to the pyridine nuclei; the ring nitrogenatoms of the pyridine being quaternized; the quatcruizing substitucntgroups of each of the quaternary ammonium groups being a member selectedfrom the class consisting of alkyl, aralkyl and alkanol groups; saidquaternary ammonium groups being neutralized by anions, which processcomprises condensing said copolymer with an aldehyde containing not morethan 3 carbon atoms and a compound selected from the class consisting ofammonia, primary and secondary aliphatic amines, and quaternizing theanion groups with a quatcrnizing agent capable of introducing groupsselected from the class consisting of alkyl, aralkyl and allcanolgroups.

13. A process for preparing a highly basic anion exchange resincomprising a copolymer of about 66% to 99.9% on a molar basis of a vinylmethyl pyridine and about 40% to 0.1% on a molar oasis of a crosslinltcrcompound selected from the class consi ting of polymerizable polyvinylaromatic and polyvinyl aliphatic com.- pounds; said vinyl methylpyridine moiety having the methyl group in a position alpha to thenitrogen of the pyridine ring; said copolymcr having quaternary ammoniummethyl groups attached to the methyl groups on the pyridine nuclei toconstitute quaternary ammonium ethyl groups attached to the pyridinenuclei in a position alpha to the nirtogen of the pyridine ring; thering nitrogen atoms of the pyridine being quatcmizcd; the quatcrnizingsubstitucnt groups of each or" the quaternary ammonium groups being amember selected from the class consisting of alkyl, aralkyl and alkanolgroups: said qua-- ternary ammonium groups being neutralized by anions.which process comprises condensing said copolymer with an aldehydecontaining not more than 3 carbon atoms and a compound selected from theclass consist ng of arm mania, primary and secondary aliphatic amines.and quaternizing the amino groups with a quaternizing agent capable ofintroducing groups selected from the class consisting of alkyl, aralkyland alkanol groups.

14. A process as defined by claim 13 wherein the vinyl, methyl pyridinemoiety is S-vinyl-Z-methyl pyridine.

15. A process as defined by claim 13 wherein the aldehyde isformaldehyde.

16. A process of producing a highly basic anion exchange resincomprising a copolymer of about 85% to 95% by weight of S-vinyl-Z-methylpyridine and about 15% t0 5% by weight of divinyl benzene; saidcopolymer having dimethylethanolammonium methyl halide groups attachedto the methyl groups on the pyridine nuclei to constitutedimethylethanolammonium ethyl halide groups attached to the pyridinering in a position alpha to the nitrogen of the pyridine ring; saidcopolymer having the ring nitrogen atoms of the pyridine ringsquaternizecl with an alkyl halide, which process comprises condensingsaid copolymer with formaldehyde and methyl ethanolamine andquaternizing the amino groups with an alkyl halide. 17. The process ofremoving anions from an aqueous solution which comprises contacting suchsolution with a highly basic anion exchange resin which is substantiallyinsoluble in water, dilute acids and alkalies, said anion exchange resinbeing one as defined by claim 1.

References Cited in the file of this patent UNITED STATES PATENTSJackson Feb. 6, 1951 Jackson Feb. 6, 1951 Kunin Dec. 18, 1951 McBurneyApr. 1, 1952 Hwa May 20, 1952 Butler Sept. 23, 1952 Bauman Oct. 14, 1952McMaster et a1 Mar. 17, 1953 Butler et a1. Aug. 24, 1954 Fakstorp Apr.24, 1956 Girod Aug. 14, 1956

1. A HIGHLY BASIC ANION EXCHANGE RESIN COMPRISING A COPOLYMER OF ABOUT60% TO 99.9% ON A MOLAR BASIC OF A VINYL METHYL PYRIDINE AND ABOUT 40%TO 0.1% ON A MOLAR BASIC OF A CROSSLINKER COMPOUND SELECTED FROM THECLASS CONSISTING OF POLYMERIZABLE POLYVINYL AROMATIC AND POLYVINYLALIPHATIC COMPOUNDS; SAID VINYL METHYL PYRIDINE MOIETY HAVING THE METHYLGROUP IN A POSITION SELECTED FROM THE GROUP CONSISTING OF THE 2,4 AND 6POSITIONS WITH RESPECT TO THE NITROGEN OF THE PYRIDINE RING; SAIDCOPOLYMER HAVING QUATERNARY AMMONIUM METHYL GROUPS ATTACHED TO THEMETHYL GROUPS OPN THE PYRIDINE NUCLEI TO CONSITITUTE QUATERNARY AMMONIUMETHYL GROUPS ATTACHED TO THE PYRIDINE NUCLEI; THE RING NITROGEN ATOMS OFTHE PYRIDINE BEING QUATERNIZED; THE QUATERNIZING SUBSTITUENT GROUPS OFEACH OF THE QUATERNARY AMMONIUM GROUPS BEING A MEMBER SELECTED FROM THECLASS CONSISTING OF ALKYL, ARALKYL AND ALKANOL GROUPS; SAID QUATERNARYAMMONINIUM GROUPS BEING NEUTRALIZED BY ANIONS.